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What am I mising? !968 Johnson 6 HP CD-25-R

carogator

Regular Contributor
Have cleaned and recleaned carb, twice before. Runs great, and refires all day, once started. Problem is that after shutdown, running carb dry for storing for a few months, it refuses to fire up again. Redo carb and it works again.
This time, realized it doesn't appear to be getting fuel, I pressurized the line to carb after it leaves fuel pump. Starts right up and runs fine, but leave overnight and problem starts again. Noticed that idle speed seems to be a little high, can't troll as slow as I would like. Have it in cleaner again. What should I look for?

Float setting is double checked each time.

Thanks for reading and ideas appreciated.
 
Some will argue------I do not believe you have a carburetor problem.----Are you prepared to do some elegantly simple testing ?
 
It was put on in rebuild and was still in place on tear downs.

Also when you blow into the fuel in line, you get fuel then air thru the carb and blow thru the fuel out line, you get nothing but pressure. No movement of air or fuel.
 
The original coils on 1968 model 3 to 40 HP have all failed !!----Have they been replaced on yours , yes , no or do not know.----Does spark jump a gap of 5/16" on both leads, yes or no ?----Original head gaskets were not the highest quality.-----Do a compression test and post your numbers.-----Replacement gaskets are improved.---Sierra is the best deal.
 
Primary circuits show continuity on both coils, secondary circuits read 5 on ohms x1 both coils, at the coil outlet and at plug wire connector. Only checked fire across plug. Need to find my fire tester.
Compression was 110 top and 108 bottom.
 
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Please answer post #3. I don't remember the exact year, but it was around that era that they started using a float needle with a soft tip. Darned things would stick in the seat during a period of non-use. Once you got it unstuck, it would run all day, no problems. That seems to describe what you said in your original post.

When the problem kept coming up, they added a wire clip to the needle to drag it off the seat when the float dropped. Problem soved.
 
Please answer post #3. I don't remember the exact year, but it was around that era that they started using a float needle with a soft tip. Darned things would stick in the seat during a period of non-use. Once you got it unstuck, it would run all day, no problems. That seems to describe what you said in your original post.

When the problem kept coming up, they added a wire clip to the needle to drag it off the seat when the float dropped. Problem soved.

I thought I answered in post #5, but Yes the clip was on each time i pulled it down. It does have the soft tip needle and from watching videos of rebuilds, I find I am more thorough than some of the ones making the videos. But I did learn one thing that might help. It seems to be recommended that instead of float being level with flange. it should be very slighltly higher on opposite end from hinge. I will try that. Am also going to look over the pump checks really good.

If all gas is run out, shouldn.t that leave the float open, since it has the clip?
 
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Assuming you have spark at the plugs that will jump a 7/16" air gap.................

The engine won't start at all... Then, each time you clean or mess with the carburetor, the engine starts. What does that tell you?

In all probability, the high speed jet located horizontally in the bottom center portion of the float chamber is fouled. Clean it!
 
Here are pictures of the needle and float with needle and clip.
Found spark tester and found jumps 1/2" but red, like really red.

High speed jet passages are open to air and liquid to the best of my knowledge.
 

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For my eyes, the float valve seems like it is worn? Because i see some scratchs on it. Is the head of the float valve sharp? How about the condition of the float valve gasket?
 
That float valve(needle) is brand new since May, 2019. Ran 2 hours at the lake, ran carb dry for the storage. Was not getting gas at startup.
 
Hi Joe, good to hear from you. To C-gator, do you store the motor standing upright? Also....try to tighten up that clip a little bit that pulls down the float. Note that when you prime it with squeeze bulb you can hear or see gas at carb. Don't use ethanol fuel.....it will damage the tip on that float needle. I prefer the brown colored tips especially here in MN where ethanol is shoved down our throats. Better yet I have a good stock of all stainless needle valves. These composit tips will soften with any ethanol. If motor is stored in laying down position, even with fuel run out, there is enough residual fuel to stick it shut. I can assure you that if you store it upright, the needle will stay open. Make sure the float arm is snug and not too sloppy on its pin....(Pappy mentioned earlier). Float must be perfectly centered so it won't rub of course. I also recommend these composit floats are set parallel with carb body.....Why? They......in the proper condition......will close the needle with a correct fuel level. You can also weigh them to see if they are failing by retaining fuel. Compare your float with a new one. I have a simple "dope" scale......and no, I "never inhaled"........right Bill? This isn't "rocket science".........but I've been humiliated with more than one of these little motors.
 
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